Department of Veterinary Medicine, School of Animal Husbandry and Food Engineering, São Paulo University - FZEA/USP, Avenida Duque de Caxias Norte, n. 225. Jardim Elite, Pirassununga, São Paulo, 13635-900, Brazil.
Department of Ecology and Evolutionary Biology, Federal University of São Paulo - UNIFESP, Diadema, São Paulo, Brazil.
Acta Parasitol. 2022 Dec;67(4):1644-1656. doi: 10.1007/s11686-022-00615-4. Epub 2022 Sep 15.
Henneguya Thélohan, 1892 is one of the most species-rich genera of myxosporean parasites and infects fish around the world. The present study describes a new species infecting the gill filaments, fins, and kidneys of Plagioscion squamosissimus (Heckel, 1840), an economically important freshwater fish distributed in watersheds in the north of South America.
A total of 108 P. squamosissimus specimens were examined from three geographic localities in the Amazon basin: the Lago Grande do Curuai, a marginal lake of the Amazon River; the Tapajós River, in the state of Pará; and the Solimões River, in the state of Amazonas, Brazil. The analyses were based on the myxospore morphology, ribosomal DNA sequencing, phylogeny, prevalence, and geographic distribution of the host and its parasite.
Parasite prevalences were 50% in both the Tapajós and Solimões rivers, and 35.4% in the Lago Grande do Curuai. In terms of the site of infection, the prevalence total was 23.1% in the gill filament, 29.6% in the fins, and 1.8% in the kidney. Regarding gender, the prevalence was 59.5% for males, 32.5% for females, and 21.7% for undetermined sex. The specimens found here were both morphologically and molecularly identical regardless of the infected organ and geographic locality, but distinct from all other Henneguya species, revealing that the parasite reported represents a novel species named Henneguya longisporoplasma n. sp. Despite the sampling being carried out in three different geographic localities of the Amazon basin, no population-level genetic variation was observed, even in the typically more variable ITS-1 region, revealing a panmictic population of H. longisporoplasma n. sp. in this large watershed. Maximum likelihood and Bayesian analyses showed the novel Henneguya clustered as a sister branch of the subclade formed of Henneguya that infect fish belonging to the family Cichlidae.
A novel Henneguya species was identified parasitizing P. squamosissimus. The parasite presented wide geographic distribution in the Amazon basin and genetic analyses showed it as revealing a panmictic population.
Henneguya Thélohan, 1892 是粘孢子虫寄生虫中物种最丰富的属之一，感染着世界各地的鱼类。本研究描述了一种新的物种，感染了 Plagioscion squamosissimus（Heckel, 1840）的鳃丝、鳍和肾脏，Plagioscion squamosissimus 是一种经济上重要的淡水鱼，分布在南美洲北部的流域。
总共检查了来自亚马逊盆地三个地理区域的 108 个 P. squamosissimus 标本： Lago Grande do Curuai，亚马逊河的一个边缘湖；Tapajós 河，位于帕拉州；以及巴西的 Solimões 河。分析基于粘孢子虫的形态学、核糖体 DNA 测序、系统发育、宿主及其寄生虫的流行率和地理分布。
在 Tapajós 和 Solimões 两条河中，寄生虫的流行率均为 50%，在 Lago Grande do Curuai 为 35.4%。就感染部位而言，总感染率为鳃丝 23.1%、鳍 29.6%、肾脏 1.8%。关于性别，雄性的流行率为 59.5%，雌性为 32.5%，未确定性别为 21.7%。无论感染的器官和地理位置如何，这里发现的标本在形态和分子上都是相同的，但与所有其他 Henneguya 物种不同，表明报告的寄生虫代表了一种新的物种，命名为 Henneguya longisporoplasma n. sp. 尽管在亚马逊盆地的三个不同地理区域进行了采样，但即使在通常更具变异性的 ITS-1 区域也没有观察到种群水平的遗传变异，这表明在这个大流域中存在着 Henneguya longisporoplasma n. sp 的混合种群。最大似然和贝叶斯分析表明，这种新的 Henneguya 聚类为感染慈鲷科鱼类的 Henneguya 亚群形成的分支的姐妹分支。
鉴定出一种新的 Henneguya 物种寄生在 P. squamosissimus 上。该寄生虫在亚马逊盆地的分布广泛，遗传分析表明它是一个混合种群。
